Fix "could not write" error missing carriage return

event.go

@@ -137,7 +137,8 @@ func (e *Event) msg(msg string) {
 		defer e.done(msg)
 	}
 	if err := e.write(); err != nil {
-		fmt.Fprintf(os.Stderr, "zerolog: could not write event: %v", err)
+		fmt.Fprintf(os.Stderr,
+			`{"%s": "zerolog: could not write event: %v"}\n`, MessageFieldName, err)
 	}
 }